Provided is a network system using diameter authentication, authorization and accounting (AAA) infrastructure to support the bootstrapping of a Mobile Internet Protocol version 6 (IPv6) mobile node. The network system includes a mobile node equipped with Mobile IPv6, an attendant which is accessed by the mobile node when the mobile node moves toward a new network, an AAA local server which supports AAA processes for the mobile node in a local network, an AAA home server which supports AAA processes for the mobile node in a home network, and supports initial settings during the bootstrapping of the mobile node, and a home agent which handles binding update (BU) and binding acknowledgement (BA) regarding the mobile node. The AAA home server can configure initial settings for the mobile node that is authenticated by the AAA local server so that the mobile node can be effectively bootstrapped. Then, the AAA home server can distribute an IPsec SA to the mobile node and a home agent, and perform BU and BA based on the initial settings.